A Kentucky mother stepped outside of her home just for a few minutes, but it was long enough for her 5-year-old son to accidentally shoot his 2-year-old sister with the .22-caliber rifle he got for his birthday, state officials said.

Little Caroline Starks died Tuesday in Burkesville, in southern Kentucky, according to Cumberland County Coroner Gary White.

"The little Crickett rifle is a single-shot rifle and it has a child safety," White said of the weapon. "It's just a tragic situation."

Starks' autopsy is scheduled for Wednesday, but the shooting has been ruled accidental, according to Kentucky State Police Public Affairs officer Billy Gregory.

"The mother was home at the time of the incident but she had stepped outside," Gregory said. "It's just one of those nightmares -- a quick thing that happens when you turn your back."

Gregory said young children in the area are often introduced to guns at an early age.

"In this part of the country, it's not uncommon for a 5-year-old to have a gun or for a parent to pass one down to their kid," he said.

The Crickett website features three different .22-caliber rifle models for kids, with shoulder stock colors ranging from pink to red, white and blue swirls. "My first rifle" is the company's slogan.

Caroline Starks' death comes in the wake of two other incidents in recent months involving young children shooting others. In early April, a 4-year-old boy in Tennessee shot and killed a 48-year-old woman, and just days later, 6-year-old Brandon Holt was killed in New Jersey after being shot in the head by his 4-year-old playmate.